I have a zigbee dongle and am looking for a matter dongle, ZBT-1 is an option though as I don’t need all its functionality, I was wondering if anyone can recommend a (cheaper) Matter/Thread dongle or device which works with HA so I can interact with Matter through HA as well.
If there are other options, e.g. not a dongle but a device (eg a smart speaker or something) that also would work, I’m all ears!
Thanks! 
Just get a skyconnect for matter over thread devices and you are set (its best to have one dedicated to zigbee mode and another dedicated to thread mode due to issues with the multipan support at the time of this reply), for matter over wifi you don’t need a dongle just connect to your HA instance when you have the matter integration setup and configured.
One of the only devices that I know of at this time that can act as a thread router and is not a dongle that is not reliant on google, apple or others is the GL-S200, I have one myself setup on my network for this dedicated role as it also does BLE passthrough via MQTT and have a skyconnect for my ZHA devices.